I cannot seem to put my IMAC to sleep manually, in the past 4 years it always workednotit does not, any ideas??
Hi, have you connected any new devices a week or so ago?
Does it Sleep if you set a time for it to sleep?
Open Console in Utilities & see if there are any clues or repeating messages when trying to manually Sleep it.
I am now using time machine with an external harddrive. If this is the problem doestht mean I have to shut down the external harddrive???
Well, as a test, eject the external try, disconnect it, then test manual Sleep.
Also Spotlight & Time Machine can prevent sleep if thry're using that drive.
by turning off the external hard drive I am now able to put computer to sleep. Does this mean that I can only back up when I am using my computer and have to disconnect it each time I want it to go to sleep?
Well, it depends on what exact drive & chipset it has... & did you install any software with that drive?
Did you add this drive to Spotlight's Privacy pane in Sys Prefs?
Retrieving data ...